34 



EISEN 



glands similar to those found in M.fuscus^ but more numerous. The 

 lower part of the penis contains a few long glands enclosed within 

 the penial sheath. 



The sperm-sacs seem unusually large and extend beyond somite 

 XVIII. 



The lyyjiphocytes were poorly preserved and their exact shape could 

 not be made out, but they appeared oval and very small. 



Nephridia (fig. 13a). — More deeply lobed than in any other spe- 

 cies, the ducts unusually large, even for a Mesenchytrceus . The 



£ore^ 



Fig. 13. Mesenchytrceus obscurus. 



nuclei all round. The inner lumen irregular and wide with a large 

 number of wide chambers. The windings shown in the figure are 

 only approximately correct. Not all the nuclei are figured, as many 

 would not stain. * 



MESENCHYTR^US MACULATUS sp. nov. 



pi. v, figs. 1-5 ; and text-fig. 14. 

 Dcjinition. — Length 45 to 60 mm., width 1.3 mm. Somites 93. 

 Head-pore far forward. Seta : laterals, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 

 2, 2, 3, 2,3; ventrals, 6, 8, 8, 8, 8, 8, 7, 6, 7, 7, o, 6, 6, 6, 6, 6, 

 etc., diminishing in size towards lateral interval. Clitellum IX, XII 

 and XIII. Sexual papillaa small, white. Brain deltoid, posteriorly 

 slightly emarginated. Dorsal vessel rises posterior to clitellum. In- 

 testine with a thick layer of brown chloragogen cells. Spermathecae 

 unusually enlarged, with two tubular diverticles at the center of the 

 duct ; the ampulla at first wide, doubled on itself, then narrower, ex- 



